There are generally two types of heat exchanger.
The first type of heat exchanger includes a bundle of "U-shaped" tubes or a bundle of straight tubes, in which a fluid circulates.
However, this type of exchanger is of expensive design and its thermal efficiency is limited, in view of the fact that the number of tubes depends on the available space, which is restricted in most cases.
The second type of heat exchanger includes a bundle of plates arranged side-by-side and mutually parallel.
The plates, consisting of thin metal sheets, most often made of stainless steel, include smooth-surfaced edges and a central part provided with corrugations via which they are in contact with one another and by which they delimit a double circuit for circulation of two independent fluids in counterflow from one end of the exchanger to the other.
The plates are connected to one another at their longitudinal edges by connection means consisting, for example, of longitudinal braces fixed together by a leaktight weld wall extending over the entire length and over the entire height of the bundle.
In addition, the plates define, a central zone for heat transfer and exchange between the fluids and, on the other hand, at each end of the bundle, a superposition of inlets and outlets for these fluids.
In prior art structure, each plate includes particular corrugations distributed in defined directions on the surface of the plate, which define the central heat transfer and exchange zone as well as the inlets and the outlets.
The inlets and the outlets are therefore formed by a superposition of corrugations which intersect, creating variations in passage cross-section for the fluids and thereby generating perturbations in their flow.